1. Field of the Invention
The invention relates to complementary engaging means of a screw and screw driver particularly adapted for use in awkard or relatively inaccessible locations where a common screw and screw driver would be inconvenient.
2. Prior Art
There is a long standing problem relating to applying torque to screws in awkward or relatively inaccessible places where the screw cannot be held temporarily by hand whilst being rotated prior to "biting" or engaging the opening into which it is being screwed. Heads of common screws are provided with engaging means to engage complementary screw driver bits, for example the slot head, Phillips or Robertson engaging means. However, none of these engaging means positively hold the screw on the screw driver so that the screw is maintained in axial alignment with the screw driver when the screw driver is held at any inclination to the horizontal. Furthermore, when torque is applied by the screw in some of the common engaging means, reaction forces are generated between the engaging means which tend to disengage the engaging means, thus causing the screw driver to slip relative to the screw.